Influencing factors and measures to reduce the temperature-induced drift of the zero signal.
1) All force sensors are designed as Wheatstone full bridges. The first and most effective measure to compensate for the temperature-related drift of the zero signal is the bridge circuit.
2) The second measure to compensate for the drift of the zero signal is by using strain gauges with so-called "self-compensation" given. These strain gauges have (in the range of approx. +10°C to 70°C) a negative temperature coefficient of the resistor. The negative coefficient is just as large as the temperature-related expansion of the sensor material would result in an increase in resistance. For aluminum, steel and titanium there are respectively adapted strain gauges.
All sensors are tested in the temperature test bench at e.g. 20°C, 80°C aged in several cycles. The temperature-dependent drift of the zero signal is measured and, if necessary, adjusted with additional temperature-dependent resistors, which are soldered into the Wheatstone bridge.
3. The insertion of a compensation is usually carried out in this way for sensors from accuracy class 0.1%. These sensors have a sufficiently large installation space to integrate the additional compensation of the zero signal.
Ultra miniature sensors, e.g. KM10, thus contain measures 1) and 2) for compensation.
The drift of the zero signal is usually specified in %FS/10K or %FS/1K (i.e. referred to the full scale value, FS).
See also: Switch-on drift, drift of the characteristic value (drift of the slope of the characteristic curve)